1. Technical Field
This disclosure is directed to wireless communications devices, and more particularly, to methods for saving power in a radio receiver implemented in a wireless communications device.
2. Description of the Related Art
In recent years, wireless devices such as smart phones and tablet computers have become increasingly sophisticated. In addition to supporting telephone calls, many mobile devices now provide access to the internet, email, text messaging, and navigation using the global positioning system (GPS). Furthermore, many mobile devices are capable of operating sophisticated applications, many of which may utilize the functionality mentioned above.
The large amount of incorporated functionality can place a significant strain on the battery life of a mobile device. As a result, many devices incorporate a variety of power saving features. Generally speaking, portions of circuitry in a wireless may be powered down when not in use in order to save power and conserve battery life.
One significant consumer of power in a wireless device is transmitter and receiver circuitry (hereinafter ‘wireless circuitry’) that enables wireless communications. A power saving technique has been developed in recent years to save power in wireless circuitry is known as discontinuous reception (or DRX). In devices utilizing DRX, portions of wireless circuitry may be powered down if there is no information (e.g., packets) to be received or transmitted. The wireless circuitry may periodically be powered on to determine if there is information to be received, and subsequently powered back down again if such a determination indicates that no new information is incoming. In one exemplary method, a device utilizing DRX may determine from a header in a transmitted packet if the information contained therein is incoming for that device. If the information is not relevant to that device, then circuitry may be powered down for at least a portion of the remainder of the packet, and subsequently powered on before the next header. Polling is another technique that may be used, wherein a device may periodically send a beacon to an access point or base station to determine if there is any information waiting for reception. If no information is awaiting reception, portions of the wireless circuitry may be powered down until the next beacon is to be transmitted.
In addition to determining if information is awaiting reception by the mobile device, neighbor cell searching may be conducted during the time when the wireless circuitry is powered up while operating in a DRX mode. Neighbor cell searching may be performed in order to enable cell reselection and handover of the mobile device from one cell to another.